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For marine applications there are four different scrubber techniques available:

  • Open: Seawater is mixed with exhaust gases to dissolve the sulphur oxides.
  • Closed: Freshwater treated with alkaline chemicals like NaOH is typically used to achieve the same effect.
  • Hybrid: Either seawater or freshwater is used to capture the sulphur oxides.
  • Dry scrubber: SO2is absorbed on a dry chemical.


It is generally estimated that scrubbing increases fuel consumption by about 1-3%, owing to an increase in engine back-pressure. Scrubber waste that is produced from the wash water needs to be treated and disposed of onshore.


Although scrubbers are yet not widely applied commercially on ships and demand is still limited, there is likely to be an increase in demand in the near future. Several companies have already committed themselves to installation of scrubbers, mainly on cruise liners.


Examples of scrubber pilot projects and commercial first-mover projects
ShipShip typeScrubber techniqueManufacturerEngine Power (MW)
Spliethoff SpicaCon-RoHybridAlfa Laval28
Ficaria SeawaysRoRoHybridAlfa Laval/MAN Diesel & Turbo21
Color Line Superspeed 2RoPaxOpen-loopWärtsilä38


Marine gas oil (MGO) mainly reduces the sulphur oxide emissions of maritime shipping because its sulphur content is lower. A lower fuel sulphur content also has a positive impact on emissions of particulates: a reduction of fuel sulphur from 2.7% to 0.1% reduces particulate emissions by 80%. The future availability and price impact of increased demand is currently being widely discussed. 


85-100% less pollutants

LNG as a shipping fuel can help significantly reduce the environmental impacts of maritime transport, most likely without increasing costs. With this fuel, NOx, SOx and particulate emissions can be reduced by 85-100% in comparison with HFO.